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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2008-09-05 09:30:14 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2008-09-08 11:35:43 -0700 |
| commit | 14469a8dd23677921db5e7354a602c98d9c6300f (patch) | |
| tree | 87aab243efb6dea0a8fb38fe6207764b24b82e6b /arch | |
| parent | 0253398ca1df7e1d2bfbb452175c964a0862482c (diff) | |
| download | linux-14469a8dd23677921db5e7354a602c98d9c6300f.tar.gz linux-14469a8dd23677921db5e7354a602c98d9c6300f.tar.bz2 linux-14469a8dd23677921db5e7354a602c98d9c6300f.zip | |
x86: disable static NOPLs on 32 bits
On 32-bit, at least the generic nops are fairly reasonable, but the
default nops for 64-bit really look pretty sad, and the P6 nops really do
look better.
So I would suggest perhaps moving the static P6 nop selection into the
CONFIG_X86_64 thing.
The alternative is to just get rid of that static nop selection, and just
have two cases: 32-bit and 64-bit, and just pick obviously safe cases for
them.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/Kconfig.cpu | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu index 2c518fbc52ec..b225219c448c 100644 --- a/arch/x86/Kconfig.cpu +++ b/arch/x86/Kconfig.cpu @@ -382,14 +382,17 @@ config X86_OOSTORE # P6_NOPs are a relatively minor optimization that require a family >= # 6 processor, except that it is broken on certain VIA chips. # Furthermore, AMD chips prefer a totally different sequence of NOPs -# (which work on all CPUs). As a result, disallow these if we're -# compiling X86_GENERIC but not X86_64 (these NOPs do work on all -# x86-64 capable chips); the list of processors in the right-hand clause -# are the cores that benefit from this optimization. +# (which work on all CPUs). In addition, it looks like Virtual PC +# does not understand them. +# +# As a result, disallow these if we're not compiling for X86_64 (these +# NOPs do work on all x86-64 capable chips); the list of processors in +# the right-hand clause are the cores that benefit from this optimization. # config X86_P6_NOP def_bool y - depends on (X86_64 || !X86_GENERIC) && (M686 || MPENTIUMII || MPENTIUMIII || MPENTIUMM || MCORE2 || MPENTIUM4 || MPSC) + depends on X86_64 + depends on (MCORE2 || MPENTIUM4 || MPSC) config X86_TSC def_bool y |